Page 77 - NEW Armstrong Book - 2

SiC Is Essential to
Advancing EV and Energy
Infrastructure
By Ryo Takeda, Takamasa Arai, and Mike Hawes
because commercially available test systems have not been readily available.
Unfortunately, it is difficult to produce repeatable and reliable measurement results with one-off, “homegrown” testers. Unreliable results create additional obstacles for power- converter designers when correlating their measurements with the semiconductor’s datasheets. A system and tech- nique for consistent, reliable characterization of WBG semi- conductors is needed. This article explores the key test chal- lenges and techniques to overcome them.
International Electrotechnical Commission (IEC) and Joint Electronic Devices Engineering Council (JEDEC) standards have existed for decades that define tests to dynamically characterize power semiconductors. The double-pulse test (DPT) setup is the industry standard used for measuring and extracting most of the key dynamic parameters to character- ize these devices (Figure 1).
These standards were sufficient for slower switch-mode power converters because the bandwidth requirements of the measurement equipment and fixturing connecting to the power semiconductor device under test (DUT) were obtain- able with standard low-frequency power design practices and measurements. The switching frequencies of power- converter designs were in the kilohertz to tens-of-kilohertz range, not requiring extensive high-frequency analysis or design.
With many power-converter markets (such as automotive/ EV and renewable energy) pushing for reduced cost, higher efficiency, higher voltages, and better thermal performance, the pressure on the power semiconductor industry has driven faster Si-based switching capabilities (Si MOSFETs and IGBTs) as well as the emergence of WBG semiconductor technologies, specifically SiC and gallium nitride.
P
ower converters are the key component to enabling the electrification of transportation and renewable energy. To facilitate needed advances in power-
converter design, new wide-bandgap (WBG) semiconductor technologies, such as silicon carbide, are being commercial- ized. WBG semiconductors provide many benefits, such as major leaps in speed (10× to 100× faster than older designs) and higher voltage and thermal operation, which in turn improve efficiency and reduce size and cost. However, the resulting high-performance power converters are proving difficult to design because of many new challenges when characterizing WBG semiconductors. Homegrown test sys- tems have been the primary source for characterizing WBG semiconductors. Building these systems has been necessary
To investigate the reason for more difficulty in mak-
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